Re: [PATCH] MdeModulePkg/BootGraphicsResourceTableDxe: don't allocate below 4 GB

["Zeng, Star" <star.zeng@intel.com>]

I am ok with this patch.

Jiewen and Liming, do you have any comments?

Thanks,
Star
-----Original Message-----
From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org] 
Sent: Monday, March 20, 2017 1:20 AM
To: edk2-devel@lists.01.org; Zeng, Star <star.zeng@intel.com>; Tian, Feng <feng.tian@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [PATCH] MdeModulePkg/BootGraphicsResourceTableDxe: don't allocate below 4 GB

The BGRT table has an 8 byte field for the memory address of the image data, and yet the driver explicitly allocates below 4 GB. This results in an ASSERT() on systems that do not have any memory below 4 GB to begin with.

Since neither the PI, the UEFI or the ACPI spec contain any mention of why this data should reside below 4 GB, replace the allocation call with an ordinary AllocatePages() call.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 MdeModulePkg/Universal/Acpi/BootGraphicsResourceTableDxe/BootGraphicsResourceTableDxe.c | 41 ++------------------
 1 file changed, 3 insertions(+), 38 deletions(-)

diff --git a/MdeModulePkg/Universal/Acpi/BootGraphicsResourceTableDxe/BootGraphicsResourceTableDxe.c b/MdeModulePkg/Universal/Acpi/BootGraphicsResourceTableDxe/BootGraphicsResourceTableDxe.c
index 804ffa5a6bb6..6a7165a95489 100644
--- a/MdeModulePkg/Universal/Acpi/BootGraphicsResourceTableDxe/BootGraphicsResourceTableDxe.c
+++ b/MdeModulePkg/Universal/Acpi/BootGraphicsResourceTableDxe/BootGraph
+++ icsResourceTableDxe.c
@@ -227,43 +227,6 @@ BgrtAcpiTableChecksum (  }
 
 /**
-  Allocate EfiBootServicesData below 4G memory address.
-
-  This function allocates EfiBootServicesData below 4G memory address.
-
-  @param[in]  Size   Size of memory to allocate.
-
-  @return Allocated address for output.
-
-**/
-VOID *
-BgrtAllocateBsDataMemoryBelow4G (
-  IN UINTN       Size
-  )
-{
-  UINTN                 Pages;
-  EFI_PHYSICAL_ADDRESS  Address;
-  EFI_STATUS            Status;
-  VOID                  *Buffer;
-
-  Pages   = EFI_SIZE_TO_PAGES (Size);
-  Address = 0xffffffff;
-
-  Status = gBS->AllocatePages (
-                  AllocateMaxAddress,
-                  EfiBootServicesData,
-                  Pages,
-                  &Address
-                  );
-  ASSERT_EFI_ERROR (Status);
-
-  Buffer = (VOID *) (UINTN) Address;
-  ZeroMem (Buffer, Size);
-
-  return Buffer;
-}
-
-/**
   Install Boot Graphics Resource Table to ACPI table.
 
   @return Status code.
@@ -358,11 +321,13 @@ InstallBootGraphicsResourceTable (
     // The image should be stored in EfiBootServicesData, allowing the system to reclaim the memory
     //
     BmpSize = (mLogoWidth * 3 + PaddingSize) * mLogoHeight + sizeof (BMP_IMAGE_HEADER);
-    ImageBuffer = BgrtAllocateBsDataMemoryBelow4G (BmpSize);
+    ImageBuffer = AllocatePages (EFI_SIZE_TO_PAGES (BmpSize));
     if (ImageBuffer == NULL) {
       return EFI_OUT_OF_RESOURCES;
     }
 
+    ZeroMem (ImageBuffer, BmpSize);
+
     mBmpImageHeaderTemplate.Size = (UINT32) BmpSize;
     mBmpImageHeaderTemplate.ImageSize = (UINT32) BmpSize - sizeof (BMP_IMAGE_HEADER);
     mBmpImageHeaderTemplate.PixelWidth = (UINT32) mLogoWidth;
--
2.7.4